Isolation of stereoisomeric epoxy carotenoids and new acetylenic carotenoid from the common freshwater goby Rhinogobius brunneus.

Stereoisomeric epoxy carotenoids with 3,5-cis configuration, diadinoxanthin B [(3S,5S,6R,3'R)-diadinoxanthin] (1) and antheraxanthin B [(3S,5S,6R,3'R)-antheraxanthin] (2), along with diadinoxanthin A [(3S,5R,6S,3'R)-diadinoxanthin] and antheraxanthin A [(3S,5R,6S,3'R)-antheraxanthin], were isolated from the common freshwater goby Rhinogobius brunneus. This is the first example in nature of 3,5-cis carotenoid epoxides. Furthermore, a new acetylenic triol carotenoid, gobiusxanthin (3), was obtained, and its structure was determined to be 7,8-didehydro-beta, epsilon-carotene-3,3', 6'-triol by chemical and spectral data.